U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  6

                                                                                
Station ID: 9459016                         PUBLICATION DATE:  04/13/2005
Name:       MITROFANIA ISLAND                                 
            AK
NOAA Chart: NONE                            Latitude:   55° 53.4' N (  55.89000)
USGS Quad:  STEPOVAC BAY (D-3)              Longitude: 158° 49.2' W (-158.82000)


To reach the bench marks from the harbor in Sand Point, AK, proceed NE 20.5 km
(11 nm) to the north point of Korovin Island, then proceed ENE 46 km (25 nm) to
the SE point of Kupreanof Point, then proceed NE 60 km (32 nm) to a west facing
cove on the north side of Mitrofania Island.  The bench marks are located in the
NE corner of the cove.  The tide gauge orifices were located approximately 110 m
offshore.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  9016 E 2004
                         DESIGNATION:          945 9016 E

MONUMENTATION:           Tidal Station disk                    VM#:        17731
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID#: BBBH57
LATITUDE:   55° 53.3' N (  55.88830)          LONGITUDE: 158° 49.1' W (-158.81800)


The primary bench mark is located 249 m (817 ft) ESE (117  magnetic) from bench
mark 9016 A 2004, 101 m (331 ft) SE (141  magnetic) from bench mark 9016 D 2004,
31 m (102 ft) south (166  magnetic) from a meandering stream in the grass and
alder flats, 30 m (98 ft) SW (221  magnetic) from the base of a grassy hill
below the most prominent rock peak in the NE corner of the cove, and 17.0 m
(55.8 ft) ENE (78  magnetic) from the top edge of the gravel beach. The datum
point is the top of a stainless steel rod set 0.01 m (0.03 ft) below grade,
driven 6.7 m (22 ft) to refusal, marked with a punch and enclosed in an 8-inch
NGS logo cap.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 9459016                         PUBLICATION DATE:  04/13/2005
Name:       MITROFANIA ISLAND                                 
            AK
NOAA Chart: NONE                            Latitude:   55° 53.4' N (  55.89000)
USGS Quad:  STEPOVAC BAY (D-3)              Longitude: 158° 49.2' W (-158.82000)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  9016 A 2004
                         DESIGNATION:          945 9016 A

MONUMENTATION:           Tidal Station disk                    VM#:        17727
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   55° 53.4' N (  55.89000)          LONGITUDE: 158° 49.3' W (-158.82200)


The bench mark is a disk set flush in a rock outcrop, 249 m (817 ft) WNW (297 
magnetic) from bench mark 9016 E 2004, 46 m (150 ft) west (264  magnetic) from
bench mark 9016 B 2004, 4.3 m (14.1 ft) NE (42  magnetic) from a triangular
pointed rock 1 m (3 ft) high, 0.6 m (2.0 ft) from the edge of the vegetation and
0.5 m (1.6 ft) below the vegetation.



                         BENCH MARK STAMPING:  9016 B 2004
                         DESIGNATION:          945 9016 B

MONUMENTATION:           Tidal Station disk                    VM#:        17728
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   55° 53.4' N (  55.89000)          LONGITUDE: 158° 49.3' W (-158.82200)


The bench mark is a disk set flush in a rock outcrop, 67 m (220 ft) west (268 
magnetic) from bench mark 9016 C 2004, 46 m (150 ft) east (84  magnetic) from
bench mark 9016 A 2004, 10 m (33 ft) sloped SSE (155  magnetic) from top of
highest point on rock outcrop, 9 m (30 ft) ESE (115  magnetic) from the end of
the arm on the rock outcrop jutting westward, 2.6 m (8.5 ft) SW (214  magnetic)
from the grass covered top of the arm of the rock outcrop jutting eastward, and
2.5 m (8.2 ft) below the grass covered top of the eastward arm of the rock
outcrop.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  6

                                                                                
Station ID: 9459016                         PUBLICATION DATE:  04/13/2005
Name:       MITROFANIA ISLAND                                 
            AK
NOAA Chart: NONE                            Latitude:   55° 53.4' N (  55.89000)
USGS Quad:  STEPOVAC BAY (D-3)              Longitude: 158° 49.2' W (-158.82000)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  9016 C 2004
                         DESIGNATION:          945 9016 C

MONUMENTATION:           Tidal Station disk                    VM#:        17729
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   55° 53.4' N (  55.89000)          LONGITUDE: 158° 49.2' W (-158.82000)


The bench mark is a disk set flush in a sandy rock outcrop at the top of the
beach underneath an alder tree, 67 m (220 ft) east (86  magnetic) from bench
mark 9016 B 2004, 35 m (115 ft) NW from bench mark 9016 D 2004, 27 m (88 ft)
east (101  magnetic) from a 1.6 m (5.2 ft) high dark grey rock on the gravel
beach, 18.9 m (62.0 ft) NNW (330  magnetic) from a 4 m (13 ft) high slightly
pointed rock on the gravel beach, 0.9 m (3.0 ft) south from the edge of the
vegetation, 0.5 m (1.6 ft) below the vegetation, and 0.5 m (1.6 ft) above the
gravel beach.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                                                
Station ID: 9459016                         PUBLICATION DATE:  04/13/2005
Name:       MITROFANIA ISLAND                                 
            AK
NOAA Chart: NONE                            Latitude:   55° 53.4' N (  55.89000)
USGS Quad:  STEPOVAC BAY (D-3)              Longitude: 158° 49.2' W (-158.82000)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  9016 D 2004
                         DESIGNATION:          945 9016 D

MONUMENTATION:           Tidal Station disk                    VM#:        17730
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   55° 53.4' N (  55.89000)          LONGITUDE: 158° 49.2' W (-158.82000)


The bench mark is a disk set flush in a low sedimentary rock outcrop, 101 m (331
ft) NW (321  magnetic) from bench mark 9016 E 2004, 35 m (115 ft) SE from bench
mark 9016 C 2004, 15.4 m (50.5 ft) NNE (21  magnetic) from a 5 m (16 ft) high
boulder on the gravel beach, 14.6 m (47.9 ft) east (96  magnetic) from the
seaward edge of a 4 m (13 ft) high rock on the beach, 8.8 m (28.9 ft) ESE (102 
magnetic) from a rock ledge at the base of a grass slope 1.4 m (4.6 ft) above
the gravel beach, and 1.0 m (3.3 ft) seaward from the vertical rock ledge at the
base of the grass slope.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                                                
Station ID: 9459016                         PUBLICATION DATE:  04/13/2005
Name:       MITROFANIA ISLAND                                 
            AK
NOAA Chart: NONE                            Latitude:   55° 53.4' N (  55.89000)
USGS Quad:  STEPOVAC BAY (D-3)              Longitude: 158° 49.2' W (-158.82000)


                            T I D A L   D A T U M S 


Tidal datums at MITROFANIA ISLAND based on:

     LENGTH OF SERIES:      4 MONTHS
     TIME PERIOD:           May 2004 - August 2004
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9459450 SAND POINT, POPOF ISLAND


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

     MEAN HIGHER HIGH WATER                     MHHW   =  2.356
     MEAN HIGH WATER                            MHW    =  2.121
     MEAN TIDE LEVEL                            MTL    =  1.266
     MEAN SEA LEVEL                             MSL    =  1.248
     MEAN LOW WATER                             MLW    =  0.410
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     9016 E 2004                                 4.446    2.325
     9016 A 2004                                 3.671    1.550
     9016 B 2004                                 2.982    0.861
     9016 C 2004                                 3.537    1.416
     9016 D 2004                                 3.319    1.198


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  6

                                                                                
Station ID: 9459016                         PUBLICATION DATE:  04/13/2005
Name:       MITROFANIA ISLAND                                 
            AK
NOAA Chart: NONE                            Latitude:   55° 53.4' N (  55.89000)
USGS Quad:  STEPOVAC BAY (D-3)              Longitude: 158° 49.2' W (-158.82000)


                             D E F I N I T I O N S


Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal
Datum Epoch.  It pertains to local mean sea level and should not be confused
with the fixed datums of North American Vertical Datum of 1988 (NAVD88).

NAVD88 is a fixed datum derived from a simultaneous, least squares, minimum
constraint adjustment of Canadian/Mexican/United States leveling observations.
Local mean sea level observed at Father Point/Rimouski, Canada was held fixed as
the single initial constraint.  NAVD88 replaces NGVD29 as the national
standard geodetic reference for heights.  Bench mark elevations relative to
NAVD88 are available from NGS through the World Wide Web at 
National Geodetic Survey.

NGVD29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded.  NGVD29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads.  NGVD29 was originally derived from a general
adjustment of the first-order leveling networks of the U.S. and Canada after
holding mean sea level observed at 26 long term tide stations as fixed.
Numerous local and wide-spread adjustments have been made since establishment in
1929.  Bench mark elevations relative to NGVD29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at 
National Geodetic Survey.

NAVD88 and NGVD29 are fixed geodetic datums whose elevation relationships to
local MSL and other tidal datums may not be consistent from one location to
another.

The Vertical Mark Number (VM#) and PID# shown on the bench mark sheet are unique
identifiers for bench marks in the tidal and geodetic databases, respectively.
Each bench mark in either database has a single, unique VM# and/or PID# assigned.
Where both VM# and PID# are indicated, both tidal and geodetic elevations are
available for the bench mark listed. The NGS's Integrated Data Base (IDB PID)
provides geodetic datum based on traditionally leveled and bluebooked ties to
the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/.
The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based
on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/.

The NAVD88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD88 elevations.
The NAVD88 elevation relationship shown in the table is derived from an average
of several bench mark elevations relative to tide station datum.  As a result of
this averaging, NAVD88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD88 elevations listed for
each bench mark in the NGS database.